Peculiarities of quantum radiation in three dimensions from moving mirrors with high refractive index

In the prefect reflector limit n --> proportional to, the photon pairs radiated by a moving three-dimensional half-space with nondispersive refractive index n = root e mu show peculiarities unheralded in 1D. The radiated power (per unit area) is different for n(2) = epsilon and n(2) = mu (cases 1 and 2, respectively). The half-space is taken to oscillate harmonically either parallel or normally to its surface, and to interact with a massless scalar field; for normal motion in case 1 (2) the power is then identical to the electromagnetic power flowing into transverse-electric (transverse-magnetic) modes from a true dielectric with n(2) = epsilon. Even in the limit, the power radiated inwards into the perfectly reflecting material remains finite, except for sideways motion in case 2. This paradoxical behaviour stems from the unfamiliar kinematics of such photon pairs, admitting peculiar and dimensionality-dependent conspiracies between vanishing matrix elements and diverging phase-space volumes. For outward radiation from normal oscillations, the perfect-reflector limits tally with those implied by results already known for the Maxwell field. For sideways oscillations, the outward power vanishes as n --> proportional to, at different rates in cases 1 and 2; but it is always dominated by photons whose partners have travelled inwards. Appendices outline the opposite regime of dilute media with n close to unity, and contrast 3D with 1D. (C) 1996 Academic Press, Inc.